BIOCOMPATIBLE COLLOIDAL SOLUTION OF GOLD NANOPARTICLES IN NON-AQUEOUS POLAR SOLVENT AND METHOD OF OBTAINING THEREOF

Abstract

The present application relates to colloidal chemistry, specifically to methods of synthesising gold nanoparticle colloids in a non-aqueous solvent, preferably, in dimethyl sulfoxide. In particular these gold nanoparticles have an average size of 5-20 nm and are in a biocompatible colloidal solution.

Claims

1. A biocompatible colloidal solution of gold nanoparticles in a non-aqueous polar solvent, preferably, in dimethyl sulfoxide, characterized in that the solution contains gold nanoparticles, obtained by reducing a gold salt, using a biocompatible reductant, which requires an alkaline medium to reduce gold ions to gold nanoparticles [Au.sup.0], and the alkaline medium is obtained with tetraalkylammonium hydroxide, and the ingredients are taken in such amount that allows obtaining nanoparticles with an average size of 5-20 nm, and the resulting colloidal solution is adjusted to neutral pH.

2. The colloid solution of claim 1, wherein ascorbic agent is a biocompatible reducing agent.

3. The colloid solution of claim 1, wherein glycerine is a biocompatible reducing agent.

4. The colloid solution of claim 1, wherein hydrogen peroxide is a biocompatible reducing agent.

5. The colloid solution of claim 1, wherein ethyl alcohol is a biocompatible reducing agent.

6. The colloid solution of claim 1, wherein glucose is a biocompatible reducing agent.

7. The colloid solution of claim 1, wherein tetraethylammonium hydroxide or tetraisopropylammonium hydroxide or tetrabutylammonium hydroxide or tetrapentylammonium hydroxide is tetraalkylammonium hydroxide.

8. The colloid solution of claim 1, wherein sodium tetrachloroaurate (III) is a gold salt.

9. The colloid solution of claim 1, wherein the average size of gold [Au.sup.0] nanoparticles is within 5-6 nm.

10. A method of obtaining a colloidal solution of gold nanoparticles in a nonaqueous polar solvent, preferably, in dimethyl sulfoxide, of claim 1, characterized in that gold salt is reduced by a biocompatible reducing agent in an alkaline medium when the solution of a gold salt and dimethyl sulfoxide interacts with a biocompatible reductant, which requires an alkaline medium to reduce gold ions to gold nanoparticles [Au.sup.0], dimethyl sulfoxide and tetraalkylammonium hydroxide, and the resulting colloidal solution is then adjusted to neutral pH.

11. The method of claim 10, wherein the resulting colloidal solution is adjusted to neutral pH by adding an organic acid to the resulting colloidal solution.

12. The method of claim 10, wherein ascorbic acid is used as a biocompatible reducing agent.

13. The method of claim 10, wherein glycerine is used as a biocompatible reducing agent.

14. The method of claim 10, wherein hydrogen peroxide is used as a biocompatible reducing agent.

15. The method of claim 10, wherein ethyl alcohol is used as a biocompatible reducing agent.

16. The method of claim 10, wherein glucose is used as a biocompatible reducing agent.

17. The method of claim 10, wherein tetraethylammonium hydroxide or tetraisopropylammonium hydroxide or tetrabutylammonium hydroxide or tetrapentylammonium hydroxide is used as tetraalkylammonium hydroxide.

18. The method of claim 10, wherein sodium tetrachloroaurate (III) is used as a gold salt.

Description

[0034] The invention disclosed herein is illustrated by the following examples of obtaining a biocompatible colloidal solution of gold nanoparticles (NPs) using ascorbic acid (AA) as a reductant or using alternative reductantsglycerine, hydrogen peroxide, ethyl alcohol and glucose, and by the following graphic materials, specifically:

[0035] FIG. 1 shows distribution by solvodynamic size (a) and absorption spectra (b) of colloidal gold NPs synthetized with tetraethylammonium hydroxide (Et.sub.4NOH, curves 1), tetrapropylammonium hydroxide (Pr.sub.4NOH, curves 2), tetrabutylammonium hydroxide (Bu.sub.4NOH, curves 3) and tetrapentylammonium hydroxide (Pt.sub.4NOH, curves 4). [Au.sup.0]=210.sup.3 mol/L, [AA]=110.sup.3 mol/L, [OH.sup.]=110.sup.2 mol/L. Cuvette1.0 mm (for this and subsequent distributions);

[0036] FIG. 2 shows electron microphotographs of colloidal gold NPs synthetized in Example 1;

[0037] FIG. 3 shows distribution by solvodynamic size (a) and absorption spectra (b) of colloidal gold NPs synthetized with various amounts of Et.sub.4NOH: 510.sup.3 mol/L (curves 1), 110.sup.2 mol/L (curves 2), 210.sup.2 mol/L (curves 3). [Au.sup.0]=210.sup.3 mol/L, [AA]=110.sup.3 mol/L, [OH.sup.]=110.sup.2 mol/L;

[0038] FIG. 4 shows distribution by solvodynamic size (a) and absorption spectra (b) of colloidal gold NPs synthetized with 110.sup.2 mol/L Et.sub.4NOH and various amounts of AA: 510.sup.4 mol/L (curves 1), 110.sup.3 mol/L (curves 2), 210.sup.3 mol/L (curves 3). [Au.sup.0]=110.sup.3 mol/L;

[0039] FIG. 5 shows distribution by solvodynamic size (a) and absorption spectra (b) of colloidal gold NPs synthetized in water (curves 1 and 2) and DMSO (curves 3 and 4) at 25 C. (curves 1 and 3) and 50 C. (curves 2 and 4). Synthesis in water: [Au.sup.0]=110.sup.3 mol/L, [AA]=110.sup.3 mol/L, [NaOH]=110.sup.2 mol/L. Synthesis in DMSO: [Au.sup.0]=110.sup.3 mol/L, [AA]=110.sup.3 mol/L, [Et.sub.4NOH]=110.sup.2 mol/L;

[0040] FIG. 6 shows distribution by solvodynamic size (a) and absorption spectra (b) of colloidal gold NPs, synthetized in water at 25 C. in the absence of post-synthesis additives (curves 1) and after adding of 810.sup.3 mol/L of acetic acid (curves 2) or 2.7 10.sup.3 M of citric acid (curves 3) at the post-synthesis stage. [Au.sup.0] 110.sup.3 mol/L, [AA]=110.sup.3 mol/L, [NaOH]=110.sup.2 mol/L;

[0041] FIG. 7 shows distribution by solvodynamic size (a) and absorption spectra (b) of gold NPs, synthetized in DMSO at 25 C. in the absence of post-synthesis additives (curves 1) and after adding 810.sup.3 mol/L of acetic acid (curves 2) or 2.7 10.sup.3 M of citric acid (curves 3) at the post-synthesis stage. [Au.sup.0]=110.sup.3 mol/L, [AA]=110.sup.3 mol/L, [Et.sub.4NOH]=110.sup.2 mol/L;

[0042] FIG. 8 shows distribution by solvodynamic size (a) and absorption spectra (b) for gold NPs, synthetized in DMSO at 25 C., using various quantities of glycerine: 0.1% (curves 1), 0.15% (curves 2), 0.25% (curves 3), 0.35% (curves 4) and 0.50% (curves 5). [Au.sup.0]=110.sup.3 mol/L, [Et.sub.4NOH]=110.sup.2 mol/L;

[0043] FIG. 9 shows distribution by solvodynamic size (a) and absorption spectra (b) for gold NPs, synthetized in DMSO at 25 C., using various quantities of glucose: 0.1% (curves 1), 0.2% (curves 2), 0.3% (curves 3), 0.4% (curves 4) and 0.50% (curves 5). [Au.sup.0]=110.sup.3 mol/L, [Et.sub.4NOH]=110.sup.2 mol/L;

[0044] FIG. 10 shows distribution by solvodynamic size (a) and absorption spectra (b) for gold NPs, synthetized in DMSO at 25 C., using various quantities of ethyl alcohol: 0.5% (curves 1), 0.75% (curves 2), 1.0% (curves 3), 1.5% (curves 4) and 2.0% (curves 5). [Au.sup.0]=110.sup.3 mol/L, [Et.sub.4NOH]=110.sup.2 mol/L;

[0045] FIG. 11 shows distribution by solvodynamic size (a) and absorption spectra (b) for gold NPs, synthetized in DMSO at 25 C., using various quantities of hydrogen peroxide (H.sub.2O.sub.2): 0.01% (curves 1), 0.02% (curves 2), 0.03% (curves 3), 0.04% (curves 4) and 0.05% (curves 5). [Au.sup.0]=110.sup.3 mol/L, [Et.sub.4NOH]=110.sup.2 mol/L;

[0046] Graphic materials, which illustrate the invention disclosed herein, and an example of the resulting biocompatible colloidal solution of gold nanoparticles and the method obtaining thereof are not intended to restrict the scope of claims thereto, but explain the essence of the invention only.

[0047] In the first panel of examples, a biocompatible colloidal solution of gold nanoparticles (NPs) was obtained using ascorbic acid (AA) as a reductant and tetraalkylammonium, hydroxides having various alkyl groups, to form an alkaline medium.

EXAMPLE NO. 1

[0048] Obtaining a biocompatible colloidal solution of gold NPs, using hydroxide tetraethylammonium. Two separate solutions were prepared first. For the first solution, 0.1 ml of 1.0 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous hydroxide tetraethylammonium (Et.sub.4NOH) solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by solvodynamic size (SDS) and colloid absorption spectrum are demonstrated by curves 1 on FIG. 1a and FIG. 1b, respectively.

[0049] For this and subsequent panels of examples, a standard magnetic mixer, 300 rpm, was used for stirring. NPs are synthetized at a room temperature in the air.

EXAMPLE NO. 2

[0050] Obtaining a biocompatible colloidal solution of gold NPs using hydroxide tetraisopropylammonium. Two separate solutions were prepared first. For the first solution, 0.1 ml of 1.0 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous hydroxide tetraisopropylammonium (Pr.sub.4NOH) solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 1a and FIG. 1b, respectively.

EXAMPLE NO. 3

[0051] Obtaining a biocompatible colloidal solution of gold NPs using tetrabutylammonium hydroxide. Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous tetrabutylammonium hydroxide (Bt.sub.4NOH) solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 1a and FIG. 1b, respectively.

EXAMPLE NO. 4

[0052] Obtaining a biocompatible colloidal solution of gold NPs using tetrapentylammonium hydroxide. Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous tetrapentylammonium hydroxide (Pt.sub.4NOH) solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 4 on FIG. 1a and FIG. 1b, respectively.

[0053] As shown in FIG. 1, distribution of gold NPs, obtained using various tetraalkylammonium hydroxides, and absorption spectra thereof are almost identical. Therefore, the subsequent syntheses were carried out, using the cheapest tetraalkylammonium hydroxide. FIG. 2 shows gold NPs, obtained with this method. The data shows, that the average size of NPs is 5-6 nm, that is consistent with findings of dynamic light scattering spectroscopy.

[0054] The second panel of examples was intended to select optimal concentration of tetraethylammonium hydroxide to obtain gold NPs, having maximum stability and minimum SDS.

EXAMPLE NO. 5

[0055] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.75 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.05 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 1 on FIG. 3a and FIG. 3b, respectively.

EXAMPLE NO. 6

[0056] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 3a and FIG. 3b, respectively.

EXAMPLE NO. 7

[0057] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.6 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.2 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 3a and FIG. 3b, respectively.

[0058] Conclusion: As demonstrated by the examples and SDS distribution (a) and absorption spectra (b) of colloid gold NPs, shown in FIG. 3, stable colloidal solutions of gold NPs with the smallest SDS are produced when 110.sup.2 mol/L tetraethylammonium hydroxide is used.

[0059] In the third panel of examples, the optimal concentration of reducing agent, ascorbic acid, was selected to produce gold NPs having maximum stability and minimum SDS.

EXAMPLE NO. 8

[0060] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.75 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.05 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 1 on FIG. 4a and FIG. 4b, respectively.

EXAMPLE NO. 9

[0061] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 4a and FIG. 4b, respectively.

EXAMPLE NO. 10

[0062] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.6 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.2 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. This formed a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 4a and FIG. 4b, respectively.

[0063] Conclusion: As demonstrated by the examples and SDS distribution (a) and absorption spectra (b) of colloid gold NPs, stable colloidal solutions of gold NPs with the smallest SDS may be produced when 110.sup.3 mol/L ascorbic acid is used.

[0064] The fourth panel of examples studied whether it is possible to obtain aqueous colloids of gold NPs, using the method disclosed herein, and what is the impact of the nature of the solvent and synthesis temperature on SDS and spectral characteristics of gold NPs.

EXAMPLE NO. 11

[0065] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of water under stirring. For the second solution, 5 mL of water, 0.1 mL of 1 mol/L of aqueous sodium hydroxide solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring at 25 C. This formed a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 1 on FIG. 5a and FIG. 5b, respectively.

EXAMPLE NO. 12

[0066] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added at 50 C. to 4.7 mL of water under stirring. For the second solution, 5 mL of water, 0.1 mL of 1 mol/L of aqueous sodium hydroxide solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed also at 50 C. Both solutions were further mixed under vigorous stirring at 50 C. This formed a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 5a and FIG. 5b, respectively.

EXAMPLE NO. 13

[0067] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring at 25 C. This formed a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 5a and FIG. 5b, respectively.

EXAMPLE NO. 14

[0068] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added at 50 C. to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed also at 50 C. Both solutions were further mixed under vigorous stirring at T=50 C. This formed a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 4 on FIG. 5a and FIG. 5b, respectively.

[0069] Conclusion: As demonstrated by the examples and SDS distribution (a) and absorption spectra (b) of gold colloids, gold NPs, produced in DMSO and water in the presence of organic hydroxides, described above, have almost identical characteristics. Furthermore, synthesis temperature and post-synthesis treatment at 25-50 C. practically do not affect the aggregation stability and average solvodynamic size of particles.

[0070] For further use in pharmacology, colloids, so obtained, should have neutral pH. The fifth panel of experiments studied the impact of neutralisation of residual alkali with citric or acetic acid in a colloid on its SDS and spectral profiles. Baseline gold colloids correspond to Examples No. 11 (water) and 13 (DMSO). Distribution of baseline gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 1 on FIG. 6a and FIG. 6b (for water) and FIG. 7a and FIG. 7b (for DMSO).

EXAMPLE NO. 15

[0071] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of water, 0.1 mL of 1 mol/L of aqueous sodium hydroxide solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. The concentration of gold in the colloid is [Au.sup.0]=110.sup.3 mol/L. 0.8 mL of 0.1 mol/L of aqueous acetic acid solution was added to the colloid. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 6a and FIG. 6b, respectively.

EXAMPLE NO. 16

[0072] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of water under stirring. For the second solution, 5 mL of water, 0.1 mL of 1 mol/L of aqueous sodium hydroxide solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. The concentration of gold in the colloid is [Au.sup.0]=110.sup.3 mol/L. 0.27 mL of 0.1 mol/L of aqueous citric acid solution was added to the colloid. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 5a and FIG. 5b, respectively.

EXAMPLE NO. 17

[0073] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. The concentration of gold in the colloid is [Au.sup.0]=110.sup.3 mol/L. 0.8 mL of 0.1 mol/L of aqueous acetic acid solution was added to the colloid. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 7a and FIG. 7b, respectively.

EXAMPLE NO. 18

[0074] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 0.1 mol/L aqueous AA solution were mixed. Both solutions were further mixed under vigorous stirring. The concentration of gold in the colloid is [Au.sup.0]=110.sup.3 mol/L. 0.27 mL of 0.1 mol/L of aqueous citric acid solution was added to the colloid. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 7a and FIG. 7b, respectively.

[0075] Conclusion: Neutralisation of residual alkali in colloids in water and DMSO by adding citric or acetic acid at a post-synthesis stage do not practically change characteristics and stability of gold NPs.

[0076] A further panel of experiments was intended to identify opportunities of obtaining gold NPs in DMSO using other biocompatible reducing agents, alternatives to ascorbic acid, in particular, such as glycerine, glucose, hydrogen peroxide and ethanol. Alternative biocompatible reducing agents may be used to relieve short-term pain syndrome associated with the presence of oxalate anion, a product of ascorbic acid oxidation, following intramuscular or intravenous administration of such medicinal product.

[0077] A further panel of experiments confirmed the possibility of using glycerine as a reducing agent in the method disclosed herein to produce a biocompatible colloidal solution of gold nanoparticles in a non-aqueous polar solvent.

EXAMPLE NO. 19

[0078] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 10% aqueous glycerine solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 1 on FIG. 8a and FIG. 8b, respectively.

EXAMPLE NO. 20

[0079] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.65 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.15 mL of 10% aqueous glycerine solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 8a and FIG. 8b, respectively.

EXAMPLE NO. 21

[0080] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.55 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.25 mL of 10% aqueous glycerine solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 8a and FIG. 8b, respectively.

EXAMPLE NO. 22

[0081] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.45 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.35 mL of 10% aqueous glycerine solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 4 on FIG. 8a and FIG. 8b, respectively.

EXAMPLE NO. 23

[0082] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.3 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.5 mL of 10% aqueous glycerine solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 5 on FIG. 8a and FIG. 8b, respectively.

[0083] The next panel of experiments confirmed the possibility to use glucose as a reducing agent in the method disclosed herein.

EXAMPLE NO. 24

[0084] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 10% aqueous glucose solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 1 on FIG. 9a and FIG. 9b, respectively.

EXAMPLE NO. 25

[0085] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.6 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.2 mL of 10% aqueous glucose solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 9a and FIG. 9b, respectively.

EXAMPLE NO. 26

[0086] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.5 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.3 mL of 10% aqueous glucose solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 9a and FIG. 9b, respectively.

EXAMPLE NO. 27

[0087] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.4 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.4 mL of 10% aqueous glucose solution were mixed. Both solutions were further mixed under vigorous stirring. This foul's a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 4 on FIG. 9a and FIG. 9b, respectively.

EXAMPLE NO. 28

[0088] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.3 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.5 mL of 10% aqueous glucose solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 5 on FIG. 9a and FIG. 9b, respectively.

[0089] The next panel of experiments confirmed the possibility to use ethyl alcohol as a reducing agent in the method disclosed herein.

EXAMPLE NO. 29

[0090] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.75 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.05 mL of 10% aqueous ethyl alcohol solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 1 on FIG. 10a and FIG. 10b, respectively.

EXAMPLE NO. 30

[0091] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.725 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.075 mL of 10% aqueous ethyl alcohol solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 10a and FIG. 10b, respectively.

EXAMPLE NO. 31

[0092] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 10% aqueous ethyl alcohol solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 10a and FIG. 10b, respectively.

EXAMPLE NO. 32

[0093] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.65 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.15 mL of 10% aqueous ethyl alcohol solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 4 on FIG. 10a and FIG. 10b, respectively.

EXAMPLE NO. 33

[0094] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.6 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.2 mL of 10% aqueous ethyl alcohol solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 5 on FIG. 10a and FIG. 10b, respectively.

[0095] The next panel of experiments confirmed the possibility to use hydrogen peroxide as a reducing agent in the method disclosed herein.

EXAMPLE NO. 34

[0096] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.7 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.1 mL of 1% aqueous hydrogen peroxide solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 1 on FIG. 11a and FIG. 11b, respectively.

EXAMPLE NO. 35

[0097] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.6 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.2 mL of 1% aqueous hydrogen peroxide solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 2 on FIG. 11a and FIG. 11b, respectively.

EXAMPLE NO. 36

[0098] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.5 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.3 mL of 1% aqueous hydrogen peroxide solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 3 on FIG. 11a and FIG. 11b, respectively.

EXAMPLE NO. 35

[0099] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.4 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.4 mL of 1% aqueous hydrogen peroxide solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 4 on FIG. 11a and FIG. 11b, respectively.

EXAMPLE NO. 36

[0100] Two separate solutions were prepared first. For the first solution, 0.1 ml of 0.1 mol/L aqueous NaAuCl.sub.4 solution was added to 4.3 mL of DMSO under stirring. For the second solution, 5 mL of DMSO, 0.1 mL of 1 mol/L of aqueous Et.sub.4NOH solution and 0.5 mL of 1% aqueous hydrogen peroxide solution were mixed. Both solutions were further mixed under vigorous stirring. This forms a solution of gold NPs, containing [Au.sup.0]=110.sup.3 mol/L. Distribution of gold NPs by SDS and colloid absorption spectrum are demonstrated by curves 5 on FIG. 11a and FIG. 11b, respectively.

[0101] Therefore, the invention disclosed herein allows obtaining a biocompatible colloidal solution of gold nanoparticles in a non-aqueous polar solvent in a form suitable for introduction of gold nanoparticles into soft dosage forms and cosmetic productsointments and creams, and obtaining a biocompatible colloidal solution of gold nanoparticles in a non-aqueous polar solvent, the use of which avoids pain associated with administration of the product.